SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e85f61daa71bce2b0451d3488202bab3d2999b3ff9812a19de95a5952092291d' 
  AND token = 'A6lyKsgMzF2eESnsESu78VHObDoFv5VGrOJfC2bVFDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}