SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c55930669fccbddc47cc42bf4f0f1f678b6f5e591e0936130764035bec75bd09' 
  AND token = 'v4u8xs5oDxT05fqCV+X7pAcFTyLN2DpNRmb9CGhN7WM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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