SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7e3e567640034314f97fc8b24298cb90ebd788feb20d5654e1d2c1b3d1f49f6' 
  AND token = 'pNt+DBhm1soP+FE/sDJgSBUcLE9gqDPcNINVSlMszBk=' 
  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"
    }
  }
}