SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12d2d59cd7648d2c4a917e9fbb777fa9146603f601e10a17e4623dca98dfa658' 
  AND token = 'glAt3LfeseOVMnegOGVYUSpp0QK574rLeSYZyJuGgiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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