SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9989cbf580e38fdbff6f97ea0da4c18b4dc870d0b3f6862ae9f1542efda15cd' 
  AND token = '9n0ObrhH0O8aQr4yVKRYowTzlNdub8+3Jmu3DtJUn2g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}